If the chain is not stretched, put it in an ultrasonic bath to clean. Dry it well (oven works, or WD40). Soak in an oil bath ...Mobil 1, or just 30w. Wipe off excess. Use whatever you use to lube from that point.

I like an oil bath to insure that everything is lubed inside. Keep the chain clean. A good wipe every few rides goes a long way.

If the chain is stretched, pitch it or make art.